The invention relates to producing and processing liquid metal in metallurgy, and, more particularly, to the manufacture of steel in ferrous metallurgy.
In the recent years technologies of producing liquid metal in metallurgy, especially in ferrous metallurgy, have been improved due to the methods of introducing various media under a liquid-metal layer and wide application of various gases to form such media. Argon, nitrogen, oxygen in combination with methane and nitrogen admixtures, have been used as such gases.
The abovementioned technological step enables to intensify homogenization of liquid metal as well as to accelerate the process of metal finishing. Steel blowing, in particular, is widely applied in steel-making and finishing techniques. A tuyere-based blowing device is applied to inject a gas into the furnace. A corresponding tuyere of such blowing device usually comprises metal tubes inside which gas-bearing operating channels are provided. A tuyere device provided with a blowing element intended for lateral oxygen injection, is widely used. In this case the central operating oxygen supply channel (intended also for supplying oxygen containing a nitrogen admixture) encompasses an operating annular channel to supply, for example, methane with a CH4 nitrogen admixture.
Continuous supplying of gas into the liquid steel has become the main problem in technologies of lateral oxygen injecting into liquid metal under a liquid-metal layer. Any interruption in gas supply results in entering liquid steel in operating channels and break-out of steel outside a steel containing unit. All the above mentioned requires guaranteed protection against steel break-outs through a steel containing unit.
Known is a blowing element of a steel making unit, which itself represents a solution to the mentioned problem, The blowing unit contains a series of interconnected sections of straight tubes providing gas bearing channels. The said sections of tubes contain portions with a capillary and a gas bearing channels (e.g., KNABL “Annual Refractory Symposium. 1 . . . 5 of July 2002). The essential drawback of this blowing unit known from the prior art is that such device can not be used to supply oxygen into a portion located below the liquid metal layer.
Known is a tuyere device designed for lateral oxygen supply below the liquid-metal layer. The tuyere contains a nest block made of refractory material incorporating an embedded sleeve. The socket unit contains a bush formed by coaxial metal tubes provided, on the side intended for introducing the liquid metal, at least one central operating channel and at least one annular operating channel, said channels being independently connected to gas supplies (e.g. EP 0 565 690 B1). This tuyere known from the prior art is very close to the inventive device with regard to essential features and has been selected as a prototype of the invention. An essential drawback of this tuyere consists in a lack of any substantial protection against break-out of a liquid metal through the operating channels. A tuyere designed in accordance with the present invention overcomes the above-described drawbacks of the prior art.